diff --git a/plugins/nginx/nginx_error b/plugins/nginx/nginx_error
index 73f77b07..9cb3d7df 100755
--- a/plugins/nginx/nginx_error
+++ b/plugins/nginx/nginx_error
@@ -80,6 +80,9 @@ GPLv3
 =cut
 
 
+set -eu
+
+
 # default environment variable values
 logpath=${logpath:-/var/log/nginx}
 
@@ -149,7 +152,7 @@ do_autoconf () {
 }
 
 
-case $1 in
+case ${1:-} in
   config)
     do_config
     # support "dirty config" capability